World War: Defense in Depth

After the catastrophe on the Somme in 1917, General Ludendorff was
persuaded by a group of his junior staff officers to withdraw to a line
running north-south behind the Canal du Nord between the Somme and the
Scarpe River. By this move he saved his troops from a second Somme and
shortened his line. More important, he gained the opportunity to
prepare on virgin ground and far away from hostilities for defensive
tactics which his bright young men, notably Colonel Fritz von Lossberg,
had evolved for divisions after observing the French use for smaller...